Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description usefully adds two things annotations cannot convey: the output is a truncated tail of the log, and the call requires a plan with host connections. It does not state the default number of lines returned or how much context surrounds the failure, leaving the agent guessing about truncation behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight clauses with zero waste: what it returns, what to use it for, and what it requires. The purpose is front-loaded before the usage and prerequisite details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description correctly carries the return-value burden by stating the output is the tail of a build log. Prerequisite and follow-up behavior are covered. The only remaining gap is the default for the optional lines parameter, which neither the schema nor the description supplies.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 33%: projectId is documented in the schema ('Project id from list_projects'), while deployId and lines are bare. The description compensates for deployId by saying it comes from deploy_status, but adds nothing about lines beyond 'the last lines' – no default value, no note that it is capped at 200.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a precise resource phrase ('the last lines of a Cloudflare Workers Builds, Vercel or Netlify build log') and ties the deployId to deploy_status, so the agent knows exactly what is returned and where the id comes from. It stops short of explicitly distinguishing this from the sibling get_logs, which a reader must infer is for a different log type.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a clear trigger ('Use it to fix a failed build') and clarifies the follow-up flow ('the fix goes live when the user publishes again'), plus the prerequisite 'Needs a plan that includes host connections.' There is no explicit when-not guidance and no sibling alternative named for non-build logs.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.